mt76x0: correct type for eeprom gain value

Change type to u8 to allow sanity check agaist 0xff;

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Fixes: e87b5039511a ("mt76x0: eeprom files")
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mediatek/mt76/mt76x0/eeprom.c

@@ -241,7 +241,7 @@ mt76x0_set_rf_freq_off(struct mt76x0_dev *dev, u8 *eeprom)
 static void
 mt76x0_set_lna_gain(struct mt76x0_dev *dev, u8 *eeprom)
 {
-	s8 gain;
+	u8 gain;
 
 	dev->ee->lna_gain_2ghz = eeprom[MT_EE_LNA_GAIN_2GHZ];
 	dev->ee->lna_gain_5ghz[0] = eeprom[MT_EE_LNA_GAIN_5GHZ_0];